In order to secure electrical fixtures such as lights and fans in ceilings, a hanger bar device is typically employed. It is very important that a fixture be adequately supported in the ceiling since improper support could lead to the fixture breaking away from the ceiling. Ceilings are typically constructed of structural members including a series of spaced joists which are covered by lathe and plaster or a gypsum wallboard. The ceiling covering material or sheathing is not designed to support loads perpendicular to its surfaces. Therefore, in order to suspend electrical fixtures from a ceiling, the fixture's weight is typically supported by the joists. To achieve this, a fixture may be secured directly to a joist; however, this limits the range of locations where the fixture may be placed. Such a limitation is problematic since it is often desirable to place the fixture in a specific position on the ceiling in order to achieve a desired lighting pattern and/or a pleasing aesthetic. Therefore, if no joist is adjacently positioned to the desired fixture location, direct joist connection is not possible. A preferred solution for supporting electrical fixtures in the ceiling is the use of a hanger bar assembly. A hanger bar allows for the joists to be used for supporting an electrical fixture while still providing flexibility in positioning a fixture.
Hanger bar assemblies typically include extensible telescopic members that are disposed in between the ceiling joists and are securable thereto. An assembly's length, therefore, is adjustable to accommodate various joist spacing distances. Electrical boxes, such as outlet boxes, junction boxes, switch boxes, and the like, are then secured to the transverse members of the hanger bar assembly. Such electrical boxes provide a termination point for electrical wiring as well as an attachment point for the electrical fixture. Typically the electrical box can be positioned at various points along the length of the members in order to properly position the fixture attached thereto. In conventional construction, a cut-out is made in the ceiling covering material in order to provide clearance for the electrical box, thereby allowing the fixture to be secured to the electrical box.
Hanger bar assemblies may be designed to support relatively heavy fixtures and ceiling fans. In order to prevent the load from pulling the assembly from the ceiling, the members forming the assembly are secured to each other to prevent them from separating from each other. The hanger bar assembly typically includes a pair of telescoping channel members with the outer member having inwardly turned edges to keep the members from separating in a direction perpendicular to or transverse to the length of the hanger bar assembly. Such hanger bar assemblies are shown in U.S. Pat. Nos. 5,934,631 and 5,938,157. However, forming the inwardly turned flanges involves additional manufacturing steps and complicates the construction.
Accordingly, it would be desirable to provide a hanger bar assembly capable of supporting differing loads including those of ceiling fans and heavy fixtures that can be efficiently manufactured.